With Bruce being "busy" both in the day and the night, it's hard to run a billion dollar company. Thankfully, he has someone he can trust in the form of Lucius Fox. Lucius Fox has been in the comics, shows, and movies, and is always one of Bruce Wayne's most trusted confidants. Many times knowing he is Batman.
Lucius is a genius in many ways, both in business savvy, and in technological prowess. Often, he is the ones who makes Bruce's "wonderful toys" including the Batmobile and Bat flyer in the Nolan films.
He is a man of great moral conviction, and is never afraid to speak his mind to Bruce because he know Bruce will listen. Lucius is second only to Alfred when it comes to the trust of Bruce Wayne.